1. Field of the Invention
The invention relates to a lens device, more particularly to a retractable lens device.
2. Description of the Related Art
Taiwanese Patent Publication No. I229231 discloses a conventional lens device adapted for use with a camera (not shown). FIGS. 1, 2 and 3 illustrate some elements of the conventional lens device 1 disclosed therein.
The conventional lens device 1 comprises a base plate 11 formed with a guide surface 111, a movable ring 12 having three guide members 121, a swingable lens module 13, and a movable barrel 14. The swingable lens module 13 has a pivot portion 131, a guide block 132 protruding from the pivot portion 131, and a lens unit 133 spaced apart from the pivot portion 131. The movable barrel 14 has an eccentric pivot 141 on which the pivot portion 131 of the swingable lens module 13 is pivoted. The movable barrel 14 further has three guide grooves 142 that engage slidably and respectively the guide members 121 of the movable ring 12 such that the movable barrel 14 is movable relative to the movable ring 12 along an optical axis (Z). The conventional lens device 1 further comprises a cam barrel (not shown) disposed for driving the movable ring 12 to move toward and away from the base plate 11 along the optical axis (Z).
When the camera is turned off, the movable barrel 14 and the movable ring 12 are driven to move toward the base plate 11 along the optical axis (Z). Since the guide block 132 of the swingable lens module 13 abuts slidably against the guide surface 111 of the base plate 11, the movements of the movable barrel 14 and the movable ring 12 drive rotation of the swingable lens module 13 about the eccentric pivot 141 of the movable barrel 14 within the movable barrel 14 to a retreating position (see FIG. 2), where the lens unit 131 of the swingable lens module 13 is away from the optical axis (Z). On the contrary, when the camera is turned on, the movable barrel 14 and the movable ring 12 are driven to move away from the base plate 11 along the optical axis (Z), and the swingable lens module 13 is biased by a torsion spring (not shown) to rotate about the eccentric pivot 141 within the movable barrel 14 to a shooting position (see FIG. 3) relative to the optical axis (Z) with the guide block 132 abutting slidably against the guide surface 111.
However, since the swingable lens module 13 is swingable within the movable barrel 14, the movable barrel 14 has a minimum size requirement for retaining pivotally the swingable lens module 13 therein, thereby obstructing the miniaturization of the conventional lens device 1.